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menu__list-item"><a class="menu__link" tabindex="0" href="/docs/v7/other-topics/utility-types/">Utility TypeScript Types</a></li></ul></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-1 menu__list-item"><a class="menu__link" href="/docs/v7/cli/">Sequelize CLI</a></li><li class="theme-doc-sidebar-item-link theme-doc-sidebar-item-link-level-1 menu__list-item"><a class="menu__link" href="/docs/v7/terminology/">Terminology</a></li></ul></nav></div></div></aside><main class="docMainContainer_TBSr"><div class="container padding-top--md padding-bottom--lg"><div class="row"><div class="col docItemCol_VOVn"><div class="theme-doc-version-banner alert alert--warning margin-bottom--md" role="alert"><div>This is unreleased documentation for Sequelize v7 - alpha version.</div><div class="margin-top--md">For up-to-date documentation, see the <a href="/docs/v6/">latest version</a> (v6 - stable).</div></div><div class="docItemContainer_Djhp"><article><nav class="theme-doc-breadcrumbs breadcrumbsContainer_Z_bl" aria-label="Breadcrumbs"><ul class="breadcrumbs" itemscope="" itemtype="https://schema.org/BreadcrumbList"><li class="breadcrumbs__item"><a aria-label="Home page" class="breadcrumbs__link" href="/"><svg viewBox="0 0 24 24" class="breadcrumbHomeIcon_YNFT"><path d="M10 19v-5h4v5c0 .55.45 1 1 1h3c.55 0 1-.45 1-1v-7h1.7c.46 0 .68-.57.33-.87L12.67 3.6c-.38-.34-.96-.34-1.34 0l-8.36 7.53c-.34.3-.13.87.33.87H5v7c0 .55.45 1 1 1h3c.55 0 1-.45 1-1z" fill="currentColor"></path></svg></a></li><li itemscope="" itemprop="itemListElement" itemtype="https://schema.org/ListItem" class="breadcrumbs__item"><a class="breadcrumbs__link" itemprop="item" href="/docs/v7/category/models--tables/">Models & Tables</a><meta itemprop="position" content="1"></li><li itemscope="" itemprop="itemListElement" itemtype="https://schema.org/ListItem" class="breadcrumbs__item breadcrumbs__item--active">Validations & Constraints<meta itemprop="position" content="2"></li></ul></nav>Version: v7 - alpha<div class="tocCollapsible_ETCw theme-doc-toc-mobile tocMobile_ITEo"><button type="button" class="clean-btn tocCollapsibleButton_TO0P">On this page</button></div><div class="ads-container mobile"></div><div class="theme-doc-markdown markdown"><header><h1>Validations & Constraints</h1></header><a href="#validators">Validations</a> are checks performed by Sequelize, in pure JavaScript. They can be arbitrarily complex if you provide a custom validator function, or can be one of the <a href="#attribute-validators">built-in validators</a> offered by Sequelize. If validation fails, no SQL query will be sent to the database at all. Constraints are rules defined at the SQL level and are enforced by the Database. Common examples are <code>UNIQUE</code>. <code>NOT NULL</code> and foreign key constraints. <h2 class="anchor anchorWithStickyNavbar_LWe7" id="not-null-constraints">Not Null Constraints<a href="#not-null-constraints" class="hash-link" aria-label="Direct link to Not Null Constraints" title="Direct link to Not Null Constraints"></a></h2> We already talked about Not Null Constraints in the <a href="/docs/v7/models/defining-models/#nullability">section about Defining Models</a>. Using the <a href='/api/v7/functions/_sequelize_core.decorators_legacy.notnull' rel='noopener noreferrer' target='_blank'><code>@NotNull</code></a> decorator, you can define a Not Null Constraint on a column. Sequelize also automatically adds a Not Null Validator to the attribute, meaning the Sequelize will also validate that the attribute is not null before sending the query to the database. If an attempt is made to set <code>null</code> to an attribute that does not allow null, a <a href='/api/v7/classes/_sequelize_core.index.validationerror' rel='noopener noreferrer' target='_blank'><code>ValidationError</code></a> will be thrown without any SQL query being performed. <h2 class="anchor anchorWithStickyNavbar_LWe7" id="unique-constraints">Unique Constraints<a href="#unique-constraints" class="hash-link" aria-label="Direct link to Unique Constraints" title="Direct link to Unique Constraints"></a></h2> Unique constraints are created as unique indexes in the database. Read more about them in the <a href="/docs/v7/models/indexes/#unique-indexes">documentation on Indexes</a>. <h2 class="anchor anchorWithStickyNavbar_LWe7" id="foreign-key-constraints">Foreign Key Constraints<a href="#foreign-key-constraints" class="hash-link" aria-label="Direct link to Foreign Key Constraints" title="Direct link to Foreign Key Constraints"></a></h2> There are two ways of defining foreign key constraints in Sequelize: <ul> <li>By <a href="/docs/v7/associations/basics/">defining an association</a> between two models (recommended).</li> <li>Using the <a href='/api/v7/interfaces/_sequelize_core.index.foreignkeyoptions#references' rel='noopener noreferrer' target='_blank'><code>references</code></a> option of the <a href='/api/v7/functions/_sequelize_core.decorators_legacy.attribute' rel='noopener noreferrer' target='_blank'><code>@Attribute</code></a> decorator.</li> </ul> <h2 class="anchor anchorWithStickyNavbar_LWe7" id="check-constraints">Check Constraints<a href="#check-constraints" class="hash-link" aria-label="Direct link to Check Constraints" title="Direct link to Check Constraints"></a></h2> <div class="theme-admonition theme-admonition-note admonition_xJq3 alert alert--secondary"><div class="admonitionHeading_Gvgb"><svg viewBox="0 0 14 16"><path fill-rule="evenodd" d="M6.3 5.69a.942.942 0 0 1-.28-.7c0-.28.09-.52.28-.7.19-.18.42-.28.7-.28.28 0 .52.09.7.28.18.19.28.42.28.7 0 .28-.09.52-.28.7a1 1 0 0 1-.7.3c-.28 0-.52-.11-.7-.3zM8 7.99c-.02-.25-.11-.48-.31-.69-.2-.19-.42-.3-.69-.31H6c-.27.02-.48.13-.69.31-.2.2-.3.44-.31.69h1v3c.02.27.11.5.31.69.2.2.42.31.69.31h1c.27 0 .48-.11.69-.31.2-.19.3-.42.31-.69H8V7.98v.01zM7 2.3c-3.14 0-5.7 2.54-5.7 5.68 0 3.14 2.56 5.7 5.7 5.7s5.7-2.55 5.7-5.7c0-3.15-2.56-5.69-5.7-5.69v.01zM7 .98c3.86 0 7 3.14 7 7s-3.14 7-7 7-7-3.12-7-7 3.14-7 7-7z"></path></svg>note</div><div class="admonitionContent_BuS1">Sequelize does not provide any way to declare Check Constraints on tables yet, but you can use the low-level <a href='/api/v7/classes/_sequelize_core.index.abstractqueryinterface#addConstraint' rel='noopener noreferrer' target='_blank'><code>QueryInterface#addConstraint</code></a> API to add one yourself.We plan on adding a way to easily declare check constraints on models. See <a href="https://github.com/sequelize/sequelize/issues/11211" target="_blank" rel="noopener noreferrer">issue #11211</a>.</div></div> This example showcases how to add a check constraint after a table has been created though <a href="/docs/v7/models/model-synchronization/"><code>sync</code></a>: <div class="language-ts codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-ts codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">import { Sequelize, Model, InferAttributes, InferCreationAttributes } from '@sequelize/core'; import { NotNull, Attribute, AfterSync } from '@sequelize/core/decorators-legacy'; import { SqliteDialect } from '@sequelize/sqlite3'; class User extends Model<InferAttributes<User>, InferCreationAttributes<User>> { @Attribute(DataTypes.STRING) @NotNull declare email: string; @AfterSync static async onSync() { await this.sequelize.queryInterface.addConstraint(this.table, { fields: ['email'], type: 'check', where: { email: { [Op.like]: '%@sequelizejs.com', }, }, }); } } const sequelize = new Sequelize({ dialect: SqliteDialect, models: [User], }); await sequelize.sync(); </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <div class="theme-admonition theme-admonition-caution admonition_xJq3 alert alert--warning"><div class="admonitionHeading_Gvgb"><svg viewBox="0 0 16 16"><path fill-rule="evenodd" d="M8.893 1.5c-.183-.31-.52-.5-.887-.5s-.703.19-.886.5L.138 13.499a.98.98 0 0 0 0 1.001c.193.31.53.501.886.501h13.964c.367 0 .704-.19.877-.5a1.03 1.03 0 0 0 .01-1.002L8.893 1.5zm.133 11.497H6.987v-2.003h2.039v2.003zm0-3.004H6.987V5.987h2.039v4.006z"></path></svg>caution</div><div class="admonitionContent_BuS1">We do not recommend using <code>sync</code> in production, as it can lead to data loss. See <a href="/docs/v7/models/model-synchronization/">Model Synchronization</a> for more information.</div></div> <h2 class="anchor anchorWithStickyNavbar_LWe7" id="validators">Validators<a href="#validators" class="hash-link" aria-label="Direct link to Validators" title="Direct link to Validators"></a></h2> Validators are JavaScript functions that are run before an instance is persisted or updated in the database. You can also run validators manually using <a href='/api/v7/classes/_sequelize_core.index.model#validate' rel='noopener noreferrer' target='_blank'><code>Model#validate</code></a>. <h3 class="anchor anchorWithStickyNavbar_LWe7" id="attribute-validators">Attribute validators<a href="#attribute-validators" class="hash-link" aria-label="Direct link to Attribute validators" title="Direct link to Attribute validators"></a></h3> Attribute validators are used to validate the value of a single attribute. Sequelize provides a number of built-in validators, through extra packages, but you can also define your own. Sequelize provides the <a href='/api/v7/functions/_sequelize_core.decorators_legacy.validateattribute' rel='noopener noreferrer' target='_blank'><code>@ValidateAttribute</code></a> decorator to define custom validators. <div class="language-ts codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-ts codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">import { Model, DataTypes } from '@sequelize/core'; import { Attribute, NotNull, ValidateAttribute } from '@sequelize/core/decorators-legacy'; class User extends Model { @Attribute(DataTypes.STRING) @NotNull @ValidateAttribute((value: unknown, user: User, attributeName: string) => { // this function will run when this attribute is validated. if (name.length === 0) { throw new Error('Name cannot be empty'); } }) declare name: string; } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="sequelizevalidatorjs"><code>@sequelize/validator.js</code><a href="#sequelizevalidatorjs" class="hash-link" aria-label="Direct link to sequelizevalidatorjs" title="Direct link to sequelizevalidatorjs"></a></h3> The <a href="https://www.npmjs.com/package/@sequelize/validator.js" target="_blank" rel="noopener noreferrer"><code>@sequelize/validator.js</code></a> package provides a number validators based on the <a href="https://www.npmjs.com/package/validator" target="_blank" rel="noopener noreferrer"><code>validator.js</code></a> package, such as email validation and regex matching. ⚠️ As indicated in the validator.js documentation, the library validates and sanitizes strings only. <div class="language-ts codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-ts codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">import { Model, DataTypes } from '@sequelize/core'; import { Attribute, NotNull } from '@sequelize/core/decorators-legacy'; import { IsEmail } from '@sequelize/validator.js'; class User extends Model { @Attribute(DataTypes.STRING) @NotNull @IsEmail declare email: string; } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> Head to <a href='/api/v7/modules/_sequelize_validator_js' rel='noopener noreferrer' target='_blank'>its TypeDoc page</a> for the list of available validators. <div class="theme-admonition theme-admonition-note admonition_xJq3 alert alert--secondary"><div class="admonitionHeading_Gvgb"><svg viewBox="0 0 14 16"><path fill-rule="evenodd" d="M6.3 5.69a.942.942 0 0 1-.28-.7c0-.28.09-.52.28-.7.19-.18.42-.28.7-.28.28 0 .52.09.7.28.18.19.28.42.28.7 0 .28-.09.52-.28.7a1 1 0 0 1-.7.3c-.28 0-.52-.11-.7-.3zM8 7.99c-.02-.25-.11-.48-.31-.69-.2-.19-.42-.3-.69-.31H6c-.27.02-.48.13-.69.31-.2.2-.3.44-.31.69h1v3c.02.27.11.5.31.69.2.2.42.31.69.31h1c.27 0 .48-.11.69-.31.2-.19.3-.42.31-.69H8V7.98v.01zM7 2.3c-3.14 0-5.7 2.54-5.7 5.68 0 3.14 2.56 5.7 5.7 5.7s5.7-2.55 5.7-5.7c0-3.15-2.56-5.69-5.7-5.69v.01zM7 .98c3.86 0 7 3.14 7 7s-3.14 7-7 7-7-3.12-7-7 3.14-7 7-7z"></path></svg>Future development</div><div class="admonitionContent_BuS1">We're working on adding support for more validation libraries, see <a href="https://github.com/sequelize/sequelize/issues/15497" target="_blank" rel="noopener noreferrer">issue #15497</a>.</div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="model-validators">Model validators<a href="#model-validators" class="hash-link" aria-label="Direct link to Model validators" title="Direct link to Model validators"></a></h3> You can also define validators that run on the whole model, rather than on a single attribute. Model validator methods are called with the model object's context and are deemed to fail if they throw an error, otherwise pass. This is just the same as with custom attribute-specific validators. For example, you could ensure that either <code>latitude</code> and <code>longitude</code> are both set, or neither are. <div class="language-ts codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-ts codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">class Place extends Model { @Attribute(DataTypes.INTEGER) declare latitude: number | null; @Attribute(DataTypes.INTEGER) declare longitude: number | null; @ModelValidator validateCoords() { if ((this.latitude === null) !== (this.longitude === null)) { throw new Error('Either both latitude and longitude, or neither!'); } } } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> If you need to validate an attribute based on the value of another attribute, we highly recommend using Model Validators instead of Attribute Validators, because Model Validators are always run, while Attribute Validators are only run if the attribute's value has changed. Model validator functions can also be static, in which case they will receive the instance to validate as the first argument: <div class="language-ts codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-ts codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">class Place extends Model { @Attribute(DataTypes.INTEGER) declare latitude: number | null; @Attribute(DataTypes.INTEGER) declare longitude: number | null; @ModelValidator static validateCoords(place: Place) { if ((place.latitude === null) !== (place.longitude === null)) { throw new Error('Either both latitude and longitude, or neither!'); } } } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></button></div></div></div> <div class="theme-admonition theme-admonition-caution admonition_xJq3 alert alert--warning"><div class="admonitionHeading_Gvgb"><svg viewBox="0 0 16 16"><path fill-rule="evenodd" d="M8.893 1.5c-.183-.31-.52-.5-.887-.5s-.703.19-.886.5L.138 13.499a.98.98 0 0 0 0 1.001c.193.31.53.501.886.501h13.964c.367 0 .704-.19.877-.5a1.03 1.03 0 0 0 .01-1.002L8.893 1.5zm.133 11.497H6.987v-2.003h2.039v2.003zm0-3.004H6.987V5.987h2.039v4.006z"></path></svg>caution</div><div class="admonitionContent_BuS1">As stated above, model validators are always run.If you did not load every attribute of a model, and you have a model validator that depends on an attribute that was not loaded, it will still run but the attribute will be <code>undefined</code>. Make sure your model validator can handle this case (for instance, by stopping validation if the attribute is <code>undefined</code>).</div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="asynchronous-validators">Asynchronous validators<a href="#asynchronous-validators" class="hash-link" aria-label="Direct link to Asynchronous validators" title="Direct link to Asynchronous validators"></a></h3> Both attribute and model validators can be asynchronous. To do so, simply return a promise from the validator function. This makes it possible to, for instance, load data from the database to validate the model. Be aware that this can have serious impacts on your application's performance. <h3 class="anchor anchorWithStickyNavbar_LWe7" id="validation-of-nullable-attributes">Validation of nullable attributes<a href="#validation-of-nullable-attributes" class="hash-link" aria-label="Direct link to Validation of nullable attributes" title="Direct link to Validation of nullable attributes"></a></h3> The nullability validation takes precedence over the attribute validation. If the value of an attribute is null, its <a href="#attribute-validators">attribute validators</a> are not executed. Only its nullability validation is run. On the other hand, <a href="#model-validators">model validators</a> are always executed, even if the value of an attribute is null. This means that you can use model validators to implement custom nullability validation: <div class="language-ts codeBlockContainer_Ckt0 theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-ts codeBlock_bY9V thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_e6Vv">import { Model, DataTypes } from '@sequelize/core'; import { Attribute, NotNull } from '@sequelize/core/decorators-legacy'; import { IsEmail } from '@sequelize/validator.js'; class User extends Model { @Attribute(DataTypes.STRING) declare name: string | null; @Attribute(DataTypes.INTEGER) declare age: number; @ModelValidator onValidate() { if (this.name === null && this.age !== 10) { throw new Error("name can't be null unless age is 10"); } } } </code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><svg 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